Shock absorber



ugl1, 1936. I -c. H. KINDL .A 2,050,953

l SHOCK ABSORBER l Filed July 50, 1932 Patented Aug. 11, 1936 UNITED STATES SHOCK ABSORBER Carl H. Kindl, Dayton, Ohio, assignor, by mesne assignments, tc General Motors Corporation, Detroit, Mich., a corporation of Delaware Application July 30, 1932, Serial No. 626,430

9 Claims.

This invention relates to improvements in hydraulic shock absorbers, particularly adapted for use on motor driven vehicles.

Various designs in hydraulic shock absorbers,

both single and double-acting, have been used to cushion or control the actions of the vehicle springs. Single-acting shock absorbers are adapted to control only the rebounding movements of the vehicle springs, said rebounding l0r movements occurring when there is a separating movement between the vehicle frame and the axles. Double-acting shock absorbers control the compression movement of the vehicle springs as well as the rebounding movement thereof. Both manually operable and automatic devices have been provided with such shock absorbers for varying the degree of resistance oered by the shock absorber to such spring actions. v

The present invention contemplates among its 2O objects the provision of an automatic control device for the hydraulic shock absorber which device will, in response to accelerative movements of the part of the vehicle to which the shock absorber is attached, adjust the shock absorber to increase its resistance to body and axle movements in proportion to said movements.

Among other objects of the invention is the utilization of fluid pressure developed within the shock absorber for the adjustment of the shock absorber,` the application of said pressure being controlled in response to and proportional to accelerative movements of the shock absorber itself.

A still further object of the invention is to adjust the shock absorber only in response to and proportionately with the accelerations in the movements of the vehicle frame to which the shock absorber is attached, and particularly to the movements of the vehicle frame in a direc- 40 tion away from the axle upon which said frame is supported by the vehicle springs.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

' Referring to the drawing, the Fig. 1 is a lon- 'fgitudinal sectional View of the shock absorber taken substantially along the line I-I of Fig. 2.

Fig. 2 is a longitudinal sectional view taken substantially along the line 2--2 of Fig. 1.

Fig. 3 is a fragmentary side view of a vehicle chassis with Wheels removed, a shock absorber (Cl. 18S-88) embodying the present invention being shown attached to the frame of the vehicle.

Referring to the drawing, the numeral 20 designates the shock absorber as a whole, the casing of the shock absorber being designated by 5 the numeral 2i. This casing provides a fluid reservoir 22 and a cylinder 23, both being in communication. A shaft 24 is journalled in bearings provided by the inwardly extending lugs 200 formed in said casing. One end of the shaft exl0 tends to. the outside of the casing and has the shock absorber operating arm 25 attached thereto. The free end of said arm is swivelly oonnected with one end of a link 26. The opposite end of said link is swivelly attached to a member 15 2l' which is secured to the vehicle axle 28 by a clamping member 29. The springs of the vehicle designated by the numeral 3E! are supported upon the axle 2g, said springs in turn supporting the vehicle frame 3l as shown in the Fig. 3. The 20 shock absorber 26 is bolted to the frame 3| by bolts passing through holes in the casing, one of said holes being shown as at 33.

The shaft 24 journalled transversely of the casing has a rocker arm attached thereto within 25 the casing, said rocker arm having a rounded head portion 36 which is adapted to engage the piston 3l reciprocably supported within the cylinder 23 for purposes of reciprocating said piston when the shock absorber operating arm 25 is 30 oscillated.

Piston 31 within the cylinder forms a compression chamber at each end thereof, the chamber 40 at the one end being termed the spring rebound control chamber and 4I at the other end 35 the spring compression control chamber. As shown in Figs. 1 and 2, the ends of the cylinder are closed by cylinder head caps 42 and 43.

Referring particularly to Fig. 1, the piston 3'! is shown comprising two portions 45 and 4S held 40 together by two bolts 4l and 48. Bolt 41 extends through a passage in the piston portion 45 and threadedly engages an aligned opening in the piston portion 46. A spring 49 is interposed bei tween the head of bolt 41 and the piston portion 40 45, thereby urging the piston portion 45 toward the piston portion 46. Similarly, bolt 48 extends through a smooth channel or passage in the piston portion 46 and threadedly engages an aligned passage in the piston portion 45, a spring 50 56 being interposed between the head of bolt 43 and the piston portion 46, thus yieldably urging the piston portion 46 toward the piston portion 45. The adjacent ends of the piston portions 45 and 46 are recesssed as at 5l and 52 pro- 55 viding a central opening for receiving the rounded head or end 36 of the rocker arm 35. A wearbutton 53 is carried by each piston portion 45 and 45 so as to be engaged by the rounded end 950i the rocker arm 35. From this it may be seen that springs 49 and 59 of the respective bolts 41 and 49 of piston portions 45 and 49 urge these piston portions toward each other so that their wear-buttons 5%I are substantially maintained in engagement with the rounded end 3S of the rocker arm.

Each piston head portion has a passage providing communication between its respective compression chamber and the intermediate chamber 292 which is formed by a bulge in the'casing and which is in constant communication with the fluid reservoir 22 and each of these passages have valve mechanisms which control the fluid flow therethrough. Inasmuch as both valve mechanisms of the respective piston head portions are alifkapnly oneri-them will be described ydetailedly.

Referring to the piston head portion 45, the passage therethrough is designated by the numeral 59. An annular valve-seat 6| is provided within the piston vhead portion 45 about the end of passage 99. The intake valve B2 is adapted to 'engage the annular seat 6| in response to the action of spring -93 which is interposed A' between Valve 52 Vand an abutment ring 54 secured within-the piston head portion 45. Valve 62 has a tubular portion 95 in which the pressure release valve '59 `-is slidably supported. This pressure release valve comprises a tubular body portion l61 having a button vhead 68 adapted to rest upon thevouter surface of the intake valve 62 as shown in Fig. 1. A spring 59 -is interposed between valve 592 and an abutment collarl 19 fastened to the tubularbody portion 61 of the pressure release valve, this spring 99 yieldably urging the button head 98 of the pressure release valve upon the outer surface of the intake valve 62. A side opening 1| in the tubular body portion 61 of the intake valve is normally within the Aconfines of the intake valve 92 and thus does not establish a flow through the intake valve until said valve is moved s o that its buttonhead 98 disengages fromithe intake valve "52, at which time the opening 1| is uncovered.

The valve `mechanism functions as follows:

In response to the movement of the piston head 45 toward 'the right as regards Fig. 1, which movement occurs when the Vehicle spring 39 is-compressed or moved toward the frame 3|, the uid in the reservoir exerting a pressure throughpassage 99 will move the entire valve mechanism including 'intake valve/92 from the annular seat 9| to establish a substantially free flow of fluid from the reservoir through passage past the valve 92 into the chamber 40. Upon reversal of this movement in response to the rebounding movement ofthe vehicle springs, that is, the movement of the vehicle springs 39 away from frame 31| piston 45 exerting a pressure upon the fluid within chamber 49, will cause said fluid, when `it has attained the proper fluid pressure, to movevalve 51 slidably within the valve 62, against the eiect of spring 99, to uncover the side opening 1'| -in said valve 91 and thereby establish a restricted 'flow of fluid from the chamber 49 through the valve 91 and its side opening 1| linto passage G9 .and thence into .the reservoir. It must be remembered at this time, however, that this latter ow will -only be established when a predeter- .to accelerative movements of the frame of the Vehicle will adjust the shock absorber to increase its resistance to body and axle movements in proportion to said movements. This device is clearly illustrated in the Fig. 2 and will now be described detailedly.

Referring particularly to Figs. 1 and 2, a duct 99 is shown within the casing leading from the spring compression control chamber 4| into a recess 9|. This recess 9| Y has portions of varyin-g diameters, 'the smallest 'or lowest portion 92 being'in communication with the spring rebound control chamber 49 through the duct 93.V The portion 94 isl that which' isY in direct Ycommunicationwith the duct99, this portion 94-beingl slightly larger indiameter than theportion 92. Interior threads are provided in the portion 94 as shown in Fig. 2. Above portion 94 is a larger diameter portion 95 forming Whatrna-y be termedthe control cylinder, the upper end of this cylinder being interiorly threaded as shown in Fig.-2. *Portion 95 is in communication with a still larger portion 96 above it, which portion 96 provides a chamber containing the inertia Weight control device-and which communicates with the reser- AVoir` 22 through auf-opening |96 in the chamber wall. Y

The threaded portion 94 of the recess 9| receives a tubularplug 91 having a crosspassage 98 incommunication with duct 90 when said plug 91 is screwed into the recess 94 so that vits bottom 4end engages with a washer provided upon the shoulder 99 presented by the two diierent diameterportions 92 and `94 of said recess. Within the hollow plug 91 'there is provided'an annular ridge forming a valve seat |09 which' extends upwardly into alignment with the cross passage 98 as shownin Fig. 2. Tubularplug 91 slidably supports a tubular valve |9|, the lower end lof which is adapted normally to rest upon the valve seat |09. This tubular valve |01 has its inner passage partially threaded to .receive the metering screw |92, this screw being hollow, the inner passage of which having a restriction |03 preferably at the upper end or head .portion of the d screw as shown in Fig. 2. The screw |92 secures a piston to the tubular valve I0 the head of said screw |92 clamping theV piston portions upon an exterior shoulder provided on the tubular valve |-9|. L'Ilhispiston comprises two metallic plates |04 and |95 between which isclamped a fibrous or leather washer |06, the outer edge of which is .bent .angularly :and'slidably engages the inner wall of the recessed portion 95 which, as has been mentioned, forms the control cylinder of the :shock absorber. Ascrew plug v|01 is secured within the interior threaded end of the cylinder portion 95, this screw plug having an interiorly threaded central opening |98 for receiving a hollow plug |99, -the hollowV plug having a, central passage designated bythe numeral I I9 which provides communication between zthe recessed portion 96 and the `control cylinder portion .95. A` spring-Hl is interposed between lthe screw `plug |91 and the piston plate |05 normally. urging.

Ythe piston valve |0| into the position in which -the'lowerend thereof engages the seat I 00.`

A ring-shaped plate H3 fits upon the casing 2| of the shock absorber about the chamber 96 therein and is maintained in proper position thereon by the cover plate H4 secured to the casing by screws H5. This cover plate H4 has proper gaskets to seal the chamber 96. The ring plate H3 has a depending earHB. Cover plate H4 has two, spaced ear members ||1 extending downwardly into the chamber 96, these ears H1 supporting a pin H8 which may be termed the hinge pin for the inertia weight element |20. The inertia weight element 20 has an extension hingedly engaging the pin I 8. Upon one edge of the weight |20 there is secured a plate |2| vto which one end of spring |22 is attached, the opposite end of said spring being anchored to the ear H6 of the ring plate H3. Normally this spring |22 lifts the weight |20 so that its upper surface engages the cover plate j| |4. In the Fig.- 2I the weight |20 is not shown in the normal position, but in the position which itassumes in response to accelerative movements of the vehicle frame 3| upwardly. The weight member |20 has van adjustable screw plug |30 arranged centrally thereof, this screw plug having a recess |3| facing the hollow screw plug |09 carried in the plug |01. A tubular extension |32 on the screw plug |09 extends into the recess |3| of the plug |30, this tubular portion slidably carrying a valve |33, said valve having a tapered end adapted to seat into the upper end of the duct or passage H0 of the screw plug |09. When the weight |20 is held in normal .position by spring |22, so that the end of its plate |2| engages the cover plate I4, valve |33 may be moved by fluid pressure away from the screw plug |09 to maintain the passage H0 open in said screw plug 09. However, in response to accelerative movements` of the shock absorber casing 2| upwardly, weight |29 will engage valve |33 and urge it upon the screw plug |09 to close the passage H0 therein.

The duct |40 shown in dotted lines in Fig. 2, leads from the chamber 96 into the duct |4| which communicates with the recessed portion 95 below the piston of valve |9|. This permits any fluid beneath the piston of valve |0| to flow freely into the chamber 96 and not to obstruct the operation of the piston valve. Chamber 96 in turn is in communication with the reservoir 22 through the hole |96 in its annular wall.

The operation of the device will now be described: when the road wheels of the vehicle strike an obstruction in the roadway, springs 30 will be compressed due to the thrust of the axle 28 toward the frame 3|. This movement of the axle toward the frame causes the link connection 26 to move the shock absorber operating arm 25 counter-clockwise as regards the Fig. 3, and thus the rocker shaft 24 will be rotated in a similar direction, resulting in-a movement of the piston 31 toward the right as regards Figs. 1 and 2. Pressure will now be exerted upon the iiuid within the chamber 4|, tending to urge the fluid from the chamber into the duct 90. The engagement of the valve |0| with the seat |00, however, will not permit iluid to flow from the duct until a pressure has been attained in said duct sufficient 'tomove valve |0| with its piston against the effect of spring HI, and when this occurs fluid may ow from duct 90 through the cross passage 98 down through the lower end of screw plug 91 into the recessed portion 92 thence through passage 93 into thespring rebound control cham- .berV 40, the piston of which is at this time moving away from the piston head cap 42 and thus increasing the size of the chamber 40. If the obstruction metby the road wheels is suicient to 5 Cause extensive movements of the piston 31 toward the right sothat a greater fluid pressure is built up withinl the said chamber 4| than can properly be relieved by valve |0|, then the fluid Vpressurerelease valve 88 inthe piston will move 10 31'. Now the pistongwill be moved toward the left as regards Figs. 1 and 2 to exert a pressure upon 20 the fluid within the chamber 40. 'I'he fluid from chamber 40 will be urged through passage 93'into therecess portion 92, thence through the tubular valve |0| and its restricted hollow screw |02 into rcylinder 95 above the piston and through passage 25 H0 in the screw plug |09 into the chamber 96, thence to the reservoir via passage |96. If the restriction |03 in the screw cap |02 is too great properly to relieve the iuid pressure, then valve |0| will be moved against the effect of spring 30 .whereby fluid will Vilow from the recessed portion 92 through cross passages 98 into the duct 90 thence to the spring compression control chamber 4 I. Excessive pressures which cannot properly be relieved by valve |0| will cause pressure release 35 valve 61 to move, whereby a flow will be established through theside opening 1| and passage 6D in the piston head'portion 45 into the reservoir 22.

`The striking of the obstruction in the highway 40 which, as has been described, urges the axle 28 toward the frame 3|, will start the frame 3| of the vehicle to move in an upwardly direction. The upward Lmovement ofthe vehicle frame, if sufliciently accelerated, will cause arelative move- 45 ment between the weight member |20 and the casing 2| of the shock absorber which casing is secured to the frame 3| of the vehicle. Consequently the valve 33 will be engaged and urged by the weight |20 to close the passage H0. Now 50 the flow aforedescribed, that is, from the chamber .40 through duct 93, recess |92 to the hollow valve |0| and the screw |02 with its orice |03, chamber containing spring IH through passage H0 will be restricted or entirely shut off and as a 55 consequence fluid pressure will begin to be built up within the chamber containing spring thereby exerting a pressure upon the piston of valve |0| so that said valve will be urged toward the seat |0| with an increasing pressure and 60 thereby increasedly restricting the fluid flow from recessed portion 92 through the hollow plug 91 through the orice presented between the valve seat |00 and valve |0| into the duct 90 through the cross passages 98. This restriction of the 65 fluid ilow through duct or passage H0 by valve |33 in response to accelerative movements of the vehicle frame 3| upwardly consequently adjusts the shock absorber automatically to increase its restriction to the rebounding movement of the 70 vehicle springs 30 thereby cushioning or retarding the said upward movement of the vehicle frame. If on theother hand the movements of the vehicle frame 3| do not reach a proper acceleration, the weight member |20 will have no 7,'5

effect to move valve |33 to -close passage :Iii and the shock absorber will be `maifnltaiifned provi-de a `substantially `soft ride.

The -spring |22 which maintains the weight .1.20 in normal positionimay :bezvaried sothat diIIel-etrt accelerationsin the .upward lmovement of the ear ibody may be A.required to render the zpressureop'ep ated piston valve -IOr-l effective toincrease restricl-tionsito the `iluid iiow from the rebound chamber to lthe com-pression chamber. At all times, however, is the pressurerrelea'se valve iavailaiile .to relieve excessive'lpressures which might buldnp within the chamber, thereby avoidingthe1pos-- sibility of breakage within the shock absorber, said pressure release valve acting primarily as a safety valve, the mai-n control being effected by the valve'iill ifor movement of Ithefvehicle springs.

`1n the `present `invention applicant has provided a device of simple structure and Ydesign adapted automatically `to adust itself in accord- `ance with the nature of the road `over which the vehicle is being operated,vsuch adjustments'being made .in response A*to accelerative movements o the vehicle trame. The iiuid pressure developed by theoperation of the shock :absorber 5is :used in `i'lhefprr-:sent invention to 'supply the motive power fto etfect adiustrnent, the application di" said power being control of an inertia f-weigiht `which, in response to accelerative movements of the vehicle frame in one direction, vcontrols the operation -o a valve, regulating `power application. f

kWlhile the iorm oi embodiment of the presen-t invention as herein disclosed, constitutes a preferred lform, it lis to be 'understood that other forms `might' be adopted, all comin-g .within the scope of the claims which follow.

What lis claimed fis `as follows:

1. An hydraulic shock absorber adapted to control both the approaching land separating movements of a vehiole'rame and axle, comprising, means -for circulating fluid within 'the `shock absorber in response't-o such movements of the vehicle'rasne and axle; meansadapted to control said 4fluid circulation; means for adjusting said control-means to vary `its restriction to the Huid `circulation; and inertia controlled'meansior rendering said adjusting means effective only -in response 'and proportionate to the accelerations -of one-of the relative movements of the vehicleffrarne and axle. Y

, 2. An hydraulic shock absorber yadapted to `controlV both the approaching and separating movements ofa vehicle frame and axle, comprising, means for circulating fluid 'Withi-nthe `shook absorber in response `to=such movements of the vehicle frame 'and ax-le; means adapted Vto control said fluid circulation; 'means 'for ladjusting said control 'means to vary its restriction to the fluid circulation; and an inertia weight controlled device adapted to render `Vsaid vadjusting `means effectiveonly in lresponse and proportionate to the accelerationspf the movement o'f the vehicle member to which the shock absorber is attached.

' 3. An hydraulic shock absorber Aadapted to Ycontrol* both the approaching and separating movements of a vehiclefframe and axle, comprising, mea-ns for crctilating iluid withinr'the shock absorber' in response to such movements ci the vehicle frame and axle; a fluid flow control device adapted to control said uid circulation; a fluid, operated means,adapted to 'adjust said 'device to vary 'its control overthefluid circulation; and 'an 'inertia weight Ycontrolled valve adapted to render 'saiduid -operatedmeansefing said valve to vary its-control upon the 'f iiow; and inertia 4weight controlled -meansadap't'- ed to render said adjusting meanslefectiveonly in .response and -lproportionate 'to accelerative movement of the vehicle part to whichthecasing is attached.

5. An hydraulic shock absorber comprising, in combination, a casing providing la cylinder; a .piston in said cylinder orming two compression chambers therein; means `adapted to establish a :flow-of fluid betweensaid chambers in 'response n toa predetermi-nedziluid-pressure therein; means vior Ydiverting a portionV of the flow of `be @tween said chambers; `means'adaptedin response toacce'lerative movements of theshock absorber casing, to restrict said diverted fluid vtiow and build up a back pressure; and'means moved by said Il'back pressure to 'actuate `-the pressure 'responsive means `to `ir-icrease its Vrestriction -to flow of fluid between 'the chambers.

le. An hydraulic sl-rockabsorber navi-ng `a fluid -n reservoir, two Vfluid compression chambers and means 'for circulating iiuid between'said chambers; a cheek-valve normally shutting offsaid lfluid `circulation jbut adapted, in response to -a predetermined 'fluid pressure in either compression chamber to establish aflow into the chamber opposite, said valve being 'adapted also to estab- Alish a iiow of fluid from the circulation oaf-duid established thereby into the liuid reservoir; an

inertia weight actuated valve adapted, in krespense .to accelerative movements of the `shock absorber, to restrict said ilow tothe reservoir; and means, responsive :to said restricted new `to the reservoir, for increasing 'the restriction by the check valveto the iiuid circulation rbetween compression chambers.

'17. An 'hydraulic shock absorber having a huid reservoir anda cylinder Within which afreciprocative piston forms 'two compression chambers;

ducts .providing communication .between the respective chambers andthe said chambers and iiuid reservoir.; a spring loaded Valve normally shuttingof communication between -the chambers and adapted to maintain communcationbetween 4one of said chambers and the fluid reservoir.; an inertia weight controlled valve adapted, in response to and proportionate to .accelerative movements of the shock absorber, to restrict .the flow `from said chamber .to 4the reservoir; vand ineensA engaging .the spring loaded valve, and adapted,.in response to-the restriction of the iiuid flow to the reservoir., vto urge said 4spring loaded valve, .increasedly Ato restrict the Lud dow -be tween the respective chambers.

B. hydraulic Lshock absorber having a casing providing a fluid reservoir and a cylinder; ,a piston in said cylinder 'forming two 'compression chambers therein.; ducts in the piston `providing communication `between said chambers; Ypressure release valves normally closing said ducts; ducts inthe casing 'connecting said'chambers'; asprirrg loaded valve normally closing communicationbetween said chambers through said Acasing ducts, said valve, however, "having a constantly open passage adapted to establish communicationme tween one of said chambers and the iiuid reservoir without movement of the valve; a uid pressure operated means for adjusting said springloaded valve; and an inertia weight controlled valve adapted to render said pressure operated means eiective to adjust the spring loaded valve in response to and proportionate to accelerations in the movement of the shock absorber casing in the one direction only.

9. An hydraulic shock absorber having a casing providing a. iluid reservoir and a cylinder within which a reciprocative piston forms two compression chambers; ducts in the piston connecting said chambers; a check-valve at each end of the piston, closing a respective duct, one check-valve acting oppositely to the other; a duct in the casing connecting the two chambers; a side-duct leading from said casing duct into the reservoir, said side-duct having an enlarged cylindrical chamber between the casing duct and reservoir; a spring loaded valve normally closing the casing duct to shut 01T communication between the chambers, said valve, however, having a constantly open passage adapted to provide constant communication between the one compression chamber and reservoir without movement of the valve; a piston in the cylindrical chamber of the side-duct, and secured to the spring loaded valve; and an inertia Weight controlled valve adapted, under iniluence of the inertia weight in response toand in proportion to accelerative movements of the casing in one direction, to close the side duct leading to the reservoir, whereby uid pressure in the cylindrical chamber will urge the piston therein to urge the valve, attached to said piston, increasedly to restrict the uid ow through the casing duct.

CARL H. KINDL. 

